Wrong rotation while moving

Have a simple script that moves an object and rotating it, i want that an object will move while rotating around its axix, but it rotes its Vector perhaps, and works wrong, Thank for any help.

using UnityEngine; using System.Collections;

public class Meteor : MonoBehaviour {

 public float speed = 10f;
  
 void OnCollisionEnter(Collision collision) 
 {
    
     Destroy(gameObject);
 }
 
 // Update is called once per frame
 void Update () 
 {     
     transform.Translate(Vector3.down * Time.deltaTime * speed);
     transform.Rotate(2, 0, 2);
 }

}